Current imbalances between parallel switching devices in a power converter half leg are reduced. A gate driver generates a nominal PWM gate drive signal for a respective half leg. A first feedback loop couples the nominal PWM gate drive signal to a gate terminal of a respective first switching device. The first feedback loop has a first mutual inductance with a current path of a first parallel switching device and has a second mutual inductance with a current path of a second parallel switching device. The first and second mutual inductances are arranged to generate opposing voltages in the first feedback loop, so that when all the parallel switching devices carry equal current then the voltages cancel.
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2. The power converter of claim 1 wherein the first mutual inductance is comprised of a first winding in the first feedback loop magnetically coupled to the respective current path of the first switching device, and wherein the second mutual inductance is comprised of a second winding in the first feedback loop magnetically coupled to the respective current path of the second switching device.
3. The power converter of claim 1 wherein the first mutual inductance includes a common source inductance of the first switching device.
A power converter system includes a first switching device and a second switching device, each configured to control power flow between an input and an output. The system also includes a first mutual inductance and a second mutual inductance, which are coupled to the switching devices to transfer energy between them. The first mutual inductance incorporates a common source inductance of the first switching device, allowing the switching device's inherent inductance to function as part of the mutual inductance structure. This integration reduces the need for additional inductive components, improving efficiency and compactness. The second mutual inductance is coupled to the second switching device, enabling bidirectional energy transfer between the input and output. The system may also include a controller to regulate the switching devices, ensuring stable power conversion. The design minimizes component count while maintaining high efficiency, making it suitable for applications requiring compact and efficient power conversion, such as renewable energy systems or electric vehicle charging.
4. The power converter of claim 1 wherein the first feedback loop further includes a loss-reduction mutual inductance with the current path of the first switching device.
5. The power converter of claim 4 wherein the first mutual inductance and the loss-reduction mutual inductance are generated by a multi-turn winding magnetically coupled to the current path of the first switching device.
6. The power converter of claim 1 further comprising second and third phase legs with respective half legs each including a plurality of parallel switching devices, wherein each switching device receives a respective gate drive signal via a respective feedback loop configured to balance currents within each respective half leg using mutual inductance of the respective feedback loop with current paths of each of the switching devices connected in parallel in the respective half leg.
7. The power converter of claim 1 wherein the first and second switching devices are comprised of a transfer-molded power module having a printed circuit board, wherein the first and second mutual inductances are comprised of conductive traces forming respective loops on the printed circuit board coinciding with regions of concentrated magnetic flux generated by current flow in the first and second switching devices.
9. The inverter of claim 8 wherein the first mutual inductance is comprised of a first winding in the first feedback loop magnetically coupled to the respective current path of the first switching device, and wherein the second mutual inductance is comprised of a second winding in the first feedback loop magnetically coupled to the respective current path of the second switching device.
10. The inverter of claim 8 wherein the first mutual inductance includes a common source inductance of the first switching device.
A power inverter converts direct current (DC) to alternating current (AC) using switching devices, such as transistors, to control the flow of electricity. A common challenge in inverter design is minimizing energy losses and improving efficiency, particularly in high-frequency applications where parasitic inductances can degrade performance. These parasitic inductances, such as the source inductance of switching devices, can cause voltage spikes, reduce efficiency, and increase electromagnetic interference. This invention addresses these issues by incorporating a mutual inductance structure in the inverter, where the first mutual inductance includes the common source inductance of the first switching device. The mutual inductance is designed to couple magnetic fields between the switching devices, reducing parasitic effects and improving energy transfer. By integrating the source inductance of the switching device into the mutual inductance, the inverter achieves tighter coupling, lower losses, and better control over the switching transitions. This design enhances efficiency, reduces voltage stress on components, and minimizes electromagnetic interference, making the inverter more reliable and suitable for high-performance applications. The mutual inductance structure can be applied in various inverter topologies, including half-bridge and full-bridge configurations, to optimize performance.
11. The inverter of claim 8 wherein the first feedback loop further includes a loss-reduction mutual inductance with the current path of the first switching device.
12. The inverter of claim 11 wherein the first mutual inductance and the loss-reduction mutual inductance are generated by a multi-turn winding magnetically coupled to the current path of the first switching device.
13. The inverter of claim 8 further comprising second and third phase legs with respective half legs each including a plurality of parallel switching devices, wherein each switching device receives a respective gate drive signal via a respective feedback loop configured to balance currents within each respective half leg using mutual inductance of the respective feedback loop with current paths of each of the switching devices connected in parallel in the respective half leg.
14. The inverter of claim 8 wherein the first and second switching devices are comprised of a transfer-molded power module having a printed circuit board, wherein the first and second mutual inductances are comprised of conductive traces forming respective loops on the printed circuit board coinciding with regions of concentrated magnetic flux generated by current flow in the first and second switching devices.
15. The inverter of claim 14 wherein the switching devices are comprised of insulated gate bipolar transistors.
This invention relates to power inverters, specifically those used in renewable energy systems like solar or wind power installations. The problem addressed is the need for efficient, reliable, and cost-effective power conversion from direct current (DC) to alternating current (AC) in such systems. Traditional inverters often use switching devices that are either inefficient or expensive, leading to higher energy losses and system costs. The inverter includes a plurality of switching devices configured to convert DC input power to AC output power. These switching devices are specifically implemented using insulated gate bipolar transistors (IGBTs). IGBTs are chosen for their high efficiency, fast switching capabilities, and ability to handle high power levels, making them well-suited for renewable energy applications. The inverter may also include additional components such as control circuitry to regulate the switching operations, ensuring stable and high-quality AC output. The use of IGBTs in the switching devices enhances the overall performance of the inverter by reducing energy losses and improving reliability. This design is particularly advantageous in renewable energy systems where efficiency and cost-effectiveness are critical.
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June 21, 2021
November 1, 2022
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